CureVac fails in pivotal Covid-19 vaccine trial with 47% efficacy

German biotech firm CureVac NV said on Wednesday its Covid-19 vaccine was only 47 per cent effective in a late-stage trial, missing the study's main goal and throwing in doubt the potential delivery of hundreds of millions of doses to the European Union.

The disappointing efficacy of the shot known as CVnCoV emerged from an interim analysis based on 134 Covid-19 cases in the study with about 40,000 volunteers in Europe and Latin America.

As CureVac's only major supply deals, the European Union in November secured up to 405 million doses of the vaccine, of which 180 million are optional. That was followed by a memorandum of understanding with Germany for another 20 million doses.

CureVac's U.S. traded shares fell 48 per cent to $49.00 in after-hours trading following the publication of the data.

The company said at least 13 virus variants accounted for the infections among the study population.

Out of the reported Covid-19 cases in the trial, 124 were sequenced to identify the variant causing the infection, it said. One case was attributable to the original version of the SARS-CoV-2 coronavirus that emerged in Chinese city of Wuhan in late 2019, while 57 per cent of the cases were caused by more highly transmissible so-called variants of concern.

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The company added that the interim results suggest the vaccine is effective in younger participants but did not prove efficacy in those above age 60, the age group most at risk for severe Covid-19.

"While we were hoping for a stronger interim outcome, we recognize that demonstrating high efficacy in this unprecedented broad diversity of variants is challenging. As we are continuing toward the final analysis with a minimum of 80 additional cases, the overall vaccine efficacy may change," said Chief Executive Franz-Werner Haas.

The stakes for CureVac and prospective buyers of its vaccine in Europe had risen after age limits were imposed on the use of the Johnson & Johnson and AstraZeneca vaccines due to a link to extremely rare but potentially fatal clotting disorders.

Shortfalls in AstraZeneca's and J&J's supply chain have also slowed the European vaccination campaign. It was also hoped that CureVac's shot could play an important role in low and middle-income countries, who have fallen far behind in the global immunisation drive.

Since starting out in 2000, Tuebingen-based CureVac has focused on so-called messenger RNA (mRNA) technology, which is also behind the success of vaccine pioneers BioNTech and partner Pfizer as well as Moderna, whose vaccines have proved more than 90 per cent effective in preventing illness.

Prior to the emergence of the highly effective vaccines, the U.S. Food and Drug Administration had targeted at least 50 per cent efficacy, which CureVac has fallen short of in the interim analysis. The World Health Organization had said it was looking for at least 70 per cent efficacy.

While late-stage trials of the BioNTech/Pfizer and Moderna vaccines were conducted when the original version of the virus was dominant, real-world data has so far suggested only somewhat weaker protection against the new variants.

CureVac, which is backed by investors Dietmar Hopp, the Gates Foundation and GlaxoSmithKline, as well as the German government, had aimed to produce up to 300 million doses of the vaccine in 2021 and up to 1 billion doses in 2022.

Manufacturing partners include Celonic Group of Switzerland, Novartis, Bayer, Fareva, Wacker and Rentschler Biopharma SE.

In a wager on CureVac's technology, Britain in February placed an initial conditional order for 50 million doses of next-generation vaccines by CureVac that build on the one that failed the interim trial analysis.

GSK agreed to collaborate with CureVac on production as well as on development of the next-generation vaccines.